Well, they are if they were added to the PD Collection. But if that's the case, they're very hard to find. If I look at the disk catalog text file, I see, for example, three titles with "Music Education" (named #1, #2, and #3) but with no authors after the titles. "Brain Busters" yields no results. So I'm now starting to question if the full disk collections themselves were released into the PD library or if programs were lifted and put on other compilation disks in the library.
But it's also entirely possible I'm in the wrong place. I poked around, and all I found was:
https://ftp.whtech.com/emulators/pc99/tigercub/ I did do a recursive search of the site before I asked FWIW.